RFID (Radio Frequency Identification) refers to a technology for reading information from a tag attached to an object by using a radio wave. Such RFID can be applied to various fields such as logistics, security and distribution and the like of objects.
By substituting the existing barcode based contact with an object by RFID, there are advantages in that information can be read at faster speed than that in the barcode, the distance limit of operation environment can be mitigated, objects can be endowed with intelligences.
With regard to this, a reader for recognizing the RFID tag has recently been mounted in a personal mobile terminal, such that the RFID technology is gradually in the trend of personalization and diversification.
Meanwhile, a conventional mobile phone with a built-in RFID reader radiates an electromagnetic wave so as to detect a tag. When several readers are scattered around a specific tag and simultaneously try to detect the specific tag, there occurs a problem in that a tag detecting operation cannot be normally performed because electromagnetic waves radiated from RFID readers are affected by each other.
With regard to this, technologies, such as “ALOHA”, “Slotted ALOHA”, “Frame Slotted ALOHA”, and “Adaptive Frame Slotted ALOHA” etc., have been conventionally applied to RFID readers in order to minimize the mentioned interference among readers. However, such conventional technologies cannot reliably solve interference among readers.